Thermal Spray Coatings
H.V.O.F. Thermal Spray Coatings
The Taskmaster High Velocity Oxygen Fuel thermal spray process provides High Density coatings with almost Negligible Porosity levels. This is a result of the high particle velocities produced by a combustion driven, high speed gas jet.
This process uses an oxygen-fuel mixture. Depending on user requirements, propylene, propane, hydrogen or natural gas may be used as the fuel in gas-fueled spray systems and kerosene as the fuel in liquid-fueled systems. The coating material, in powdered form, is fed axially through the gun, generally using nitrogen as a carrier gas. The fuel is thoroughly mixed with oxygen within the gun and the mixture is then ejected from a nozzle and ignited outside the gun. The ignited gases surround and uniformly heat the powdered spray material as it exits the gun and is propelled to the work piece surface. As a result of the high kinetic energy transferred to the particles through the HVOF process, the coating material generally does not need to be fully melted. Instead, the powder particles are in a molten state and flatten plastically as they impact the work piece surface. The resulting coatings have very predictable chemistries that are homogeneous and have a fine granular structure.
These coatings can survive harsh service conditions, particularly in wear and many corrosion applications, which greatly increase component service life. The smooth, as-sprayed surface, uniform chemistry and low porosity of the coating can be finished to very smooth surface profiles.
Features of the HVOF Spray Process:
· Produces very clean, hard and dense coatings with fine, homogeneous structures
· Coatings are tenaciously bonded to the substrate
· Low to compressive coating stress allows very thick coatings
· Excellent for wear and corrosion resistance
· Recommended for carbide coatings and often recommended for superalloy coatings
· Very thick coatings are possible
· Surface finishes are generally smooth and can be used in the as-sprayed condition
· Coatings can be ground and/or super finished
Work piece temperatures can be controlled to prevent changes in the microstructure. In general for optimum coating quality, temperatures should never exceed 300 degrees.
Taskmaster Technologies Inc. offers a turnkey process, which includes robotic manipulation for control and accuracy, and years of experience in generating application procedures, that can save your company time and money. In addition, our finishing equipment allows us to meet very tight tolerance and surface finish requirements depending upon application specifications.
Flame Spray / Spray and Fuse
Taskmaster can provide traditional low velocity flame spray coatings for many applications. Alloys for general repair and build up as well as wear and corrosion resistance are readily available. Common alloys applied are aluminum bronze, stainless steels, and nickel or cobalt base.
Many products are also designed for a secondary fusing process ( spray and fuse ) giving the coating a very strong capillary bond similar to that of brazing and eliminating the inherent porosity of the "as sprayed" product. Common applications for this process are: pistons, plungers, thermowells, and washpipes.
Surface Blast / Shot peen
Surface blast preparation is a critical element of our coating application performance. In addition, Taskmaster can also provide blasting services for many other applications such as:
- Glass bead for surface decontamination or cleaning of corroded / dirty components.
- Grit Blasting with a variety of available grit sizes and materials to create a clean, rough surface profile that enhances grip and coating bond strength .
- Shot Peen from 110 to 780 grit sizes for stress relieving of surface tension on critical machined parts.
